4U App working devices in UK?

[GreenAppleFields]

I've been trying to use Mr Blinky's 4U app from a couple of my old phones that are listed as compatible but it's not working at all. I'm not sure how to even check if it might be the NFC on my 4U or on my phones that is not working? Does anyone know of any device working with the app in the UK of recent? I've seen some Nexus 7 for sale, pretty cheap refurbished, but saw some people having no luck with those either, so would like to be more sure before purchasing. Thank you for any insight!

 

[devaconzuper]

it has to be a nexus 7 2013 2nd gen. a nexus 6p could also work. which phones do you have that don't seem to be working? remember to turn on nfc and android beam.